The present invention relates to containers and, in particular, it concerns a knock-down bin with locking corner assemblies.
It is known to provide containers of many types for transporting produce, manufactured articles, raw materials etc. from one location to another. Such containers are generally configured to be lifted by a fork-lift vehicle and are stackable. These containers, typically referred to as "bins", "box-pallets", "crates" or "totes", will be referred to generically herein as "bins".
In many cases, molded polymer containers are chosen for their light weight, robustness and long usable lifetime. To realize the maximum strength of the polymer materials, polymer bins are often molded in a single piece. As a result, however, they occupy the same volume when transported empty on a return journey as when full on an outbound journey. This extremely inefficient use of space is very costly.
Various disassembling or foldable bins have been developed in an attempt to reduce the transport volume requirements when the bins are empty. All such bins which either disassemble (i.e., come apart into separate elements) or fold (i.e., with all elements remaining interconnected) are referred to generically herein as "knock-down bins". An example of a foldable bin may be found in U.S. Pat. No. 5,094,356 to Miller. An example of a bin which disassembles may be found in U.S. Pat. No. 5,638,973 to Dewey et al.
While offering more efficient use of volume for lightweight applications, knock-down bins generally suffer from a number of disadvantages. Specifically, in many cases, the bins are complicated and inconvenient to assemble and disassemble, requiring a predefined sequence of non-trivial steps. A further problem associated specifically with bins which disassemble into separate elements is the number of elements which must be handled. In addition to the base and sides, a number of additional connecting elements must typically be handled separately. The loss of these elements may render the bin unusable. Furthermore, even the base and the sides once separated become much less convenient to handle.
An additional problem specific to folding bins results from the interconnected nature of the elements which renders the entire container useless if any one element is broken. Furthermore, the height of the walls is usually limited to the dimensions of the base to allow compact folding. This latter limitation can be circumvented by providing multiple hinges in the walls, or by locating a single hinge at a higher position in the wall. Each of these solutions, however, suffers from its own disadvantages, in the first case reducing the strength of the structure and, in the second, wasting space when folded.
Finally reference is made to U.S. Pat. No. 5,505,323 to Naoki et al. This reference relates to a metal container which can be disassembled. To avoid use of nut and bolts, an arrangement of interlocking projections and recesses is used to lock the sides to the base. The projections and recesses are formed so that they can be freely engaged and disengaged by inclining the side relative to the base, but become locked together when the side is brought into an upright position. The upright position is maintained primarily by a clip applied to keep together the upper edges of the sides, in some cases supplemented by a self-locking barb associated with the locking arrangement itself.
There is therefore a need for a knock-down bin formed from molded polymer materials which would provide a strong and durable locking configuration without increasing the number of separate elements which must be handled when the bin is disassembled. It would also be highly advantageous to provide a knock-down bin the sides of which, when collapsed, would fit within another such assembled bin, thereby facilitating convenient and compact return transport of the bins when not in use.